Problem: Solve for $q$ : $-22 = q - 15$
Answer: Add $15$ to both sides: $ \begin{eqnarray} \\ \hphantom{-22 {+ 15}} &\hphantom{=}& \hphantom{q} \\ -22 &=& q - 15 \\ \\ {+15} && {+15} \\ \end{eqnarray} $ $ \begin{eqnarray} \\ -22 {+ 15} &=& q \\ \end{eqnarray} $ Simplify. $ q = -7$